Insomnia and Autonomic Function Predict Well-Being in Patients Receiving Palliative Care.

Abstract

The improvement of health-related quality of life (HRQOL) is one of the main treatment goals in end-of-life care. Although definitions and conceptualizations remain heterogeneous, many researchers proposed HRQOL to be considered as subjective patient well-being. However, research on its determinants in palliative care is rare, and little is known about the interplay between psychological and biological variables. The aim of this study was to explain differences in terminally ill patients' acute well-being (AWB) by use of a multimethod approach, examining both self-ratings and physiological predictors. The study was conducted on a palliative care unit in Heidelberg, Germany. A total of 69 adult patients receiving palliative care were included in the analysis. Patients filled out the EORTC QLQ-C15-PAL questionnaire and an additional single-item visual analogue scale on AWB. In addition, we recorded a five-minute segment of beat-to-beat fluctuations of heart rate (i.e., heart rate variability, HRV) and calculated three indices of cardiac autonomic function: mean heart rate, the root mean square of successive differences, and the standard deviation of normal-to-normal (SDNN) intervals. Exploratory, multiple regression analyses were used to identify significant predictors among the QLQ subscales and HRV parameters. Insomnia (p < 0.001) and SDNN (p < 0.001) were significantly associated with AWB and together explained 26.3% of the variance. All other predictors including pain, fatigue, and physical functioning failed to reach significance (all p > 0.05). Both autonomic dysfunction and sleep disturbances independently explained differences in patient's AWB among terminally ill patients. Their role within the concept of quality of life needs to be further addressed in future studies.